This invention relates to an inflator for use with a catheter having an inflatable component. The inflatable component may include, for example, the balloon of an angioplasty catheter or the balloon or everting element of a linear everting catheter.
Known inflators of this type typically include a housing having a plunger passage and a plunger manually movable in the plunger passage to force fluid out a port of the housing and to the inflatable component of the catheter. The inflatable component of the catheter, in combination with the inflator and any tubing or conduit between these two components, form a closed chamber. In use of the inflater and the catheter, it is important for the physician to know the pressure of the fluid in this closed chamber. To accomplish this, inflators typically include a pressure gage.
One type of pressure gage used with inflators is a circular or dial type pressure gage. Inflators with dial type pressure gages are illustrated, for example, in Nordquest U.S. Pat. No. 4,743,230, Goodin et al U.S. Pat. No. 4,723,938 and Lundquist U.S. Pat. No. 4,439,185.
Linear pressure gages are generally more economical than dial pressure gages. It is known to incorporate a linear pressure gage into the plunger of an inflator as shown, for example, by Leveen et al U.S. Pat. No. 4,346,708. However, the incorporation of a linear pressure gage into the plunger tends to interfere with the manual manipulation of the plunger if the gage is allowed to project from the handle end of the plunger.